Pool/Spa Gas Heater Gas Line Pipes Rusting! How Concerned should I be?

[Millty]

The gas line pipes to our pool/spa gas heater are rusting. The heater and pool are less than two years old. They started rusting fairly soon after installation and I should have called the company sooner, but we've had other issues, and this got put on the back burner so to speak.

It seems to me of all the pipes that should not rust are ones carrying natural gas. Did my installer use the wrong type of pipes or should he have painted them? Seems crazy that within a few months of installation they started rusting. How concerned should I be? Having so many issues on my plate now, don't know if I should get some rustoleum type paint and paint the pipes and hope for the best or is this something the contractor should rectify? Our state requires that contractors stand behind their work for two years so they are still under warranty so to speak, but I only have a couple months left.

Here's a picture of the rusting gas pipes. Having trouble attaching photos so hope this works.

 

[CJadamec]

He use galvanized steel which is exactly the right thing to use. The parts that have rust are the threads where the galvanized coating has was disturbed when the threads were cut. I would say that rust is minor but if you are concerned a quick coat of paint will solve your problems. The best thing to use there is cold galvanizing spray paint. It will recoat the pipe in zinc and stop the rust and never peal off. Next best is Rust-Oleum rusty metal primer followed by a top coat. Rust-Oleum will start to peal after a few years because galvanized steel doesn't like being painted​.

 

[Millty]

Excellent, thanks. So glad it is something we can handle and don't have to call another contractor to try and get an issue fixed.

 

[ps0303]

I've replaced rusted thru galvanized pipe that has been installed for over 10 years. It takes a long time for the pipes to rust thru. What you are seeing is surface rust and although you might feel it's unsightly, it is normal.

 

[swimcmp]

Not 100% on this but I do believe gas line is supposed to be black iron pipe not galvanized. I know here in Missouri no one will plumb gas line with galvanized. Maybe it is just a local thing.

 

[CJadamec]

The NFPA allows for the use of black iron or hot dipped galvanized steel pipe. Local codes will dictate further what is allowed to be used to best suit the local environment. Local codes will also differ on what is allowed to be used inside a residential dwelling and how it needs to be labeled.

There is anecdotal argument against galvanized pipe which says it will slough off coating on the inside of the pipe and lead to valve/regulator issues. A simple drip leg, which is seen in this installation, will solve this issue. Another argument is that galvanized pipe is more expensive and there is not guarantee it will last longer than regular black iron pipe in a lot of cases. So there is also economic incentive not to use it.

 

[lcpt]

Thank you

 

[1poolman1]

The NFPA allows for the use of black iron or hot dipped galvanized steel pipe. Local codes will dictate further what is allowed to be used to best suit the local environment. Local codes will also differ on what is allowed to be used inside a residential dwelling and how it needs to be labeled.

There is anecdotal argument against galvanized pipe which says it will slough off coating on the inside of the pipe and lead to valve/regulator issues. A simple drip leg, which is seen in this installation, will solve this issue. Another argument is that galvanized pipe is more expensive and there is not guarantee it will last longer than regular black iron pipe in a lot of cases. So there is also economic incentive not to use it.

The naturally occurring Sulphur that comes with natural gas is very corrosive to galvanized pipe (zinc) and is the reason black-iron is specified. In the US, the amount of Sulphur in the gas is restricted so it is not usually a problem using galvanized. The thin layer of rust on the outside of a pipe actually acts as a protectant, slowing the amount of damage that will occur if it were removed from these pipes and allowed to re-form. A quick shot of paint to make it pretty works well.

 

[ps0303]

The naturally occurring Sulphur that comes with natural gas is very corrosive to galvanized pipe (zinc) and is the reason black-iron is specified. In the US, the amount of Sulphur in the gas is restricted so it is not usually a problem using galvanized. The thin layer of rust on the outside of a pipe actually acts as a protectant, slowing the amount of damage that will occur if it were removed from these pipes and allowed to re-form. A quick shot of paint to make it pretty works well.

We use galvanized pipe on gas all day long here in Florida and that is code. No black pipe. I have replaced 20 plus year old heaters and the galvanized pipe is just fine.

 

[1poolman1]

We use galvanized pipe on gas all day long here in Florida and that is code. No black pipe. I have replaced 20 plus year old heaters and the galvanized pipe is just fine.

Never said it won't work, wasn't done, etc., seen it many times myself. Just that black pipe is called for in many locales and Sulphur in natural gas that used to not be limited is the reason. No real reason now and I haven't seen an inspector not sign off on a galvanized installation.